Power semiconductor devices are widely used as electrical power conversion devices in consumer electronics, industrial machines, motor vehicles and high-speed trains, etc. By means of the improvements on the structure, the improvements of the performance are achieved year by year. Compared with a planar device, a power device using groove technology provides a channel width with an obvious increase per unit area. In addition, a semiconductor device using groove technology provides an excellent switch characteristic and is used in applications having requirements for fast switching.
In accordance with United States patent application US2012/0104555A1, an IGBT having a planar gate is described, wherein the IGBT exhibits a shielding electrode in a groove, which shielding electrode is isolated from a gate electrode and connected to a source terminal. Furthermore, this IGBT has an n-layer in the upper part of a drift region with a higher doping concentration than that of the drift region.
In addition, in accordance with German patent application DE10007415C2, a power device controlled by a metal oxide semiconductor (MOS) having a planar gate is described, wherein the power device also exhibits a shielding electrode in a groove, which shielding electrode is isolated from a gate electrode and connected to a source terminal.
However, the IGBT device of the prior art has a high voltage drop in a conducting state and a poor blocking capability. Therefore, there is a need for a device having a good blocking capability and having a low voltage drop in a conducting state of the device.